Vendor import of OpenSSH.

1 files changed, 320 insertions, 0 deletions

diff --git a/crypto/openssh/cipher.c b/crypto/openssh/cipher.c
new file mode 100644
index 0000000..552bbe3
--- /dev/null
+++ b/crypto/openssh/cipher.c
@@ -0,0 +1,320 @@
+/*
+ * 
+ * cipher.c
+ * 
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * 
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * 
+ * Created: Wed Apr 19 17:41:39 1995 ylo
+ * 
+ */
+
+#include "includes.h"
+RCSID("$Id: cipher.c,v 1.19 2000/02/22 15:19:29 markus Exp $");
+
+#include "ssh.h"
+#include "cipher.h"
+
+#include <ssl/md5.h>
+
+/*
+ * What kind of tripple DES are these 2 routines?
+ *
+ * Why is there a redundant initialization vector?
+ *
+ * If only iv3 was used, then, this would till effect have been
+ * outer-cbc. However, there is also a private iv1 == iv2 which
+ * perhaps makes differential analysis easier. On the other hand, the
+ * private iv1 probably makes the CRC-32 attack ineffective. This is a
+ * result of that there is no longer any known iv1 to use when
+ * choosing the X block.
+ */
+void
+SSH_3CBC_ENCRYPT(des_key_schedule ks1,
+		 des_key_schedule ks2, des_cblock * iv2,
+		 des_key_schedule ks3, des_cblock * iv3,
+		 unsigned char *dest, unsigned char *src,
+		 unsigned int len)
+{
+	des_cblock iv1;
+
+	memcpy(&iv1, iv2, 8);
+
+	des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT);
+	memcpy(&iv1, dest + len - 8, 8);
+
+	des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT);
+	memcpy(iv2, &iv1, 8);	/* Note how iv1 == iv2 on entry and exit. */
+
+	des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT);
+	memcpy(iv3, dest + len - 8, 8);
+}
+
+void
+SSH_3CBC_DECRYPT(des_key_schedule ks1,
+		 des_key_schedule ks2, des_cblock * iv2,
+		 des_key_schedule ks3, des_cblock * iv3,
+		 unsigned char *dest, unsigned char *src,
+		 unsigned int len)
+{
+	des_cblock iv1;
+
+	memcpy(&iv1, iv2, 8);
+
+	des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT);
+	memcpy(iv3, src + len - 8, 8);
+
+	des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT);
+	memcpy(iv2, dest + len - 8, 8);
+
+	des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT);
+	/* memcpy(&iv1, iv2, 8); */
+	/* Note how iv1 == iv2 on entry and exit. */
+}
+
+/*
+ * SSH uses a variation on Blowfish, all bytes must be swapped before
+ * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
+ */
+static void
+swap_bytes(const unsigned char *src, unsigned char *dst_, int n)
+{
+	/* dst must be properly aligned. */
+	u_int32_t *dst = (u_int32_t *) dst_;
+	union {
+		u_int32_t i;
+		char c[4];
+	} t;
+
+	/* Process 8 bytes every lap. */
+	for (n = n / 8; n > 0; n--) {
+		t.c[3] = *src++;
+		t.c[2] = *src++;
+		t.c[1] = *src++;
+		t.c[0] = *src++;
+		*dst++ = t.i;
+
+		t.c[3] = *src++;
+		t.c[2] = *src++;
+		t.c[1] = *src++;
+		t.c[0] = *src++;
+		*dst++ = t.i;
+	}
+}
+
+void (*cipher_attack_detected) (const char *fmt,...) = fatal;
+
+static inline void
+detect_cbc_attack(const unsigned char *src,
+		  unsigned int len)
+{
+	return;
+
+	log("CRC-32 CBC insertion attack detected");
+	cipher_attack_detected("CRC-32 CBC insertion attack detected");
+}
+
+/*
+ * Names of all encryption algorithms.
+ * These must match the numbers defined in cipher.h.
+ */
+static char *cipher_names[] =
+{
+	"none",
+	"idea",
+	"des",
+	"3des",
+	"tss",
+	"rc4",
+	"blowfish"
+};
+
+/*
+ * Returns a bit mask indicating which ciphers are supported by this
+ * implementation.  The bit mask has the corresponding bit set of each
+ * supported cipher.
+ */
+
+unsigned int 
+cipher_mask()
+{
+	unsigned int mask = 0;
+	mask |= 1 << SSH_CIPHER_3DES;		/* Mandatory */
+	mask |= 1 << SSH_CIPHER_BLOWFISH;
+	return mask;
+}
+
+/* Returns the name of the cipher. */
+
+const char *
+cipher_name(int cipher)
+{
+	if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) ||
+	    cipher_names[cipher] == NULL)
+		fatal("cipher_name: bad cipher number: %d", cipher);
+	return cipher_names[cipher];
+}
+
+/*
+ * Parses the name of the cipher.  Returns the number of the corresponding
+ * cipher, or -1 on error.
+ */
+
+int
+cipher_number(const char *name)
+{
+	int i;
+	for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
+		if (strcmp(cipher_names[i], name) == 0 &&
+		    (cipher_mask() & (1 << i)))
+			return i;
+	return -1;
+}
+
+/*
+ * Selects the cipher, and keys if by computing the MD5 checksum of the
+ * passphrase and using the resulting 16 bytes as the key.
+ */
+
+void 
+cipher_set_key_string(CipherContext *context, int cipher,
+		      const char *passphrase, int for_encryption)
+{
+	MD5_CTX md;
+	unsigned char digest[16];
+
+	MD5_Init(&md);
+	MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase));
+	MD5_Final(digest, &md);
+
+	cipher_set_key(context, cipher, digest, 16, for_encryption);
+
+	memset(digest, 0, sizeof(digest));
+	memset(&md, 0, sizeof(md));
+}
+
+/* Selects the cipher to use and sets the key. */
+
+void 
+cipher_set_key(CipherContext *context, int cipher,
+	       const unsigned char *key, int keylen, int for_encryption)
+{
+	unsigned char padded[32];
+
+	/* Set cipher type. */
+	context->type = cipher;
+
+	/* Get 32 bytes of key data.  Pad if necessary.  (So that code
+	   below does not need to worry about key size). */
+	memset(padded, 0, sizeof(padded));
+	memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));
+
+	/* Initialize the initialization vector. */
+	switch (cipher) {
+	case SSH_CIPHER_NONE:
+		/*
+		 * Has to stay for authfile saving of private key with no
+		 * passphrase
+		 */
+		break;
+
+	case SSH_CIPHER_3DES:
+		/*
+		 * Note: the least significant bit of each byte of key is
+		 * parity, and must be ignored by the implementation.  16
+		 * bytes of key are used (first and last keys are the same).
+		 */
+		if (keylen < 16)
+			error("Key length %d is insufficient for 3DES.", keylen);
+		des_set_key((void *) padded, context->u.des3.key1);
+		des_set_key((void *) (padded + 8), context->u.des3.key2);
+		if (keylen <= 16)
+			des_set_key((void *) padded, context->u.des3.key3);
+		else
+			des_set_key((void *) (padded + 16), context->u.des3.key3);
+		memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
+		memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
+		break;
+
+	case SSH_CIPHER_BLOWFISH:
+		BF_set_key(&context->u.bf.key, keylen, padded);
+		memset(context->u.bf.iv, 0, 8);
+		break;
+
+	default:
+		fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
+	}
+	memset(padded, 0, sizeof(padded));
+}
+
+/* Encrypts data using the cipher. */
+
+void 
+cipher_encrypt(CipherContext *context, unsigned char *dest,
+	       const unsigned char *src, unsigned int len)
+{
+	if ((len & 7) != 0)
+		fatal("cipher_encrypt: bad plaintext length %d", len);
+
+	switch (context->type) {
+	case SSH_CIPHER_NONE:
+		memcpy(dest, src, len);
+		break;
+
+	case SSH_CIPHER_3DES:
+		SSH_3CBC_ENCRYPT(context->u.des3.key1,
+				 context->u.des3.key2, &context->u.des3.iv2,
+				 context->u.des3.key3, &context->u.des3.iv3,
+				 dest, (unsigned char *) src, len);
+		break;
+
+	case SSH_CIPHER_BLOWFISH:
+		swap_bytes(src, dest, len);
+		BF_cbc_encrypt(dest, dest, len,
+		               &context->u.bf.key, context->u.bf.iv,
+			       BF_ENCRYPT);
+		swap_bytes(dest, dest, len);
+		break;
+
+	default:
+		fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type));
+	}
+}
+
+/* Decrypts data using the cipher. */
+
+void 
+cipher_decrypt(CipherContext *context, unsigned char *dest,
+	       const unsigned char *src, unsigned int len)
+{
+	if ((len & 7) != 0)
+		fatal("cipher_decrypt: bad ciphertext length %d", len);
+
+	switch (context->type) {
+	case SSH_CIPHER_NONE:
+		memcpy(dest, src, len);
+		break;
+
+	case SSH_CIPHER_3DES:
+		/* CRC-32 attack? */
+		SSH_3CBC_DECRYPT(context->u.des3.key1,
+				 context->u.des3.key2, &context->u.des3.iv2,
+				 context->u.des3.key3, &context->u.des3.iv3,
+				 dest, (unsigned char *) src, len);
+		break;
+
+	case SSH_CIPHER_BLOWFISH:
+		detect_cbc_attack(src, len);
+		swap_bytes(src, dest, len);
+		BF_cbc_encrypt((void *) dest, dest, len,
+			       &context->u.bf.key, context->u.bf.iv,
+			       BF_DECRYPT);
+		swap_bytes(dest, dest, len);
+		break;
+
+	default:
+		fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type));
+	}
+}